1. Field of the Invention
The present invention relates to a blowing fan assembly, and more particularly, to a blowing fan assembly which is applied to a window-type air conditioner.
2. Description of the Related Art
Generally, as shown in FIG. 1, a window-type air conditioner has a single case 10. In the case 10, there are arranged a compressor 12 for compressing refrigerant, a condenser 14 for condensing the refrigerant which is compressed by the compressor 12, thereby decreasing the temperature of the refrigerant, and an evaporator 16 for performing a heat-exchanging function using the refrigerant which is reduced in terms of its temperature by the condenser 14.
The space which is defined in the case 10 of the window-type air conditioner is divided into an indoor portion and an outdoor portion by a partition panel 18.
The evaporator 16 and a blowing fan assembly 20 for circulating room air through the evaporator 16 are disposed in the indoor portion. The compressor 12, the condenser 14, an axial-flow fan 30 for enabling the condenser 14 to conduct a condensing function using outside air, and the like are disposed in the outdoor part.
Here, the blowing fan assembly 20 possesses, as shown in FIG. 2, a scroll case 22 which defines an air passage and a turbofan 24 which is located inside the scroll case 22. A front surface of the scroll case 22 is defined, as shown in FIGS. 3 and 4, with a suction opening 22a which has a bell mouth-shaped contour and through which the room air is sucked into the scroll case 22. Also, the front surface of the scroll case 22 is defined, at a side of the suction opening 22a, with a discharge opening 22b. 
The turbofan 24 is connected to a driving motor 40. The turbofan 24 is composed of a hub 241, a plurality of blades 242 which are located at a predetermined separation from the hub 241, and a shroud 243 which is attached to the distal ends of the plurality of blades 242 and opposite to the hub 241.
By the blowing fan assembly 20, constructed as mentioned above, warm air in the room passes through the evaporator 16 by the rotating action of the turbofan 24 and is thereby cooled. Thereafter, the cooled air is drawn into the scroll case 22 through the suction opening 22a. Then, the drawn-in air is compressed by the plurality of blades 242 and discharged from the scroll case 22 through the discharging opening 22b. In this way, the temperature of the air in the room is properly adjusted so as to cool the room.
At this time, the cooled air which is discharged out of the scroll case 22, is not immediately re-drawn into the scroll case 22 due to a static pressure increase effect which is induced inside the scroll case 22 by the presence of the shroud 243, but instead, is dispersed over a remote region.
The refrigerant which is raised in its temperature by being brought into contact with the warm air at the evaporator 16, is re-cooled, in the course of passing through the condenser 14, by the outside air which flows into the outdoor portion by the rotating action of the axial-flow fan 30, so as to be continuously circulated.
On the other hand, in the blowing fan assembly for a conventional window-type air conditioner, a sirocco fan (not shown) can be used in place of the turbofan 24. In this regard, because the sirocco fan has a large air-blowing rate, the size of the sirocco fan can be decreased. However, when assuming that the turbofan 24 and the sirocco fan have the same air blowing rate, since the sirocco fan has increased power consumption in comparison with the turbofan 24, the sirocco fan has the disadvantage that its operating efficiency is degraded.
As a consequence, the turbofan 24, which has a higher operating efficiency than the sirocco fan, is frequently used for a blowing fan assembly. Due to the fact that the turbofan 24 occupies an increased volume when compared to the sirocco fan having the same air blowing rate, in order to accomplish an efficient blowing function using the turbofan, a sufficient air blowing passage must be secured in the scroll case 22.
Thus, because the size of an air conditioner to which the turbofan 24 is applied, is larger than that of an air conditioner to which a sirocco fan of the same air blowing rate is applied, the blowing fan assembly including the aforementioned turbofan 24 adversely affects miniaturization of the air conditioner.
Moreover, in a state wherein the scroll case 22 of the blowing fan assembly, to which the turbofan 24 is applied, has the same size as that of the blowing fan assembly to which the sirocco fan is applied, if the rotational velocity of the turbofan 24 is raised so as to accomplish the desired blowing function, a problem is created in that operating noise of the driving motor 40 is increased.
Accordingly, the present invention has been made in an effort to solve the problems occurring in the related art, and thus an object of the present invention is to provide a blowing fan assembly for a window-type air conditioner, in which a scroll case is configured in such a way as to enlarge the air passage, whereby an efficient blowing function is enabled without experiencing an increase in a volume of the entire blowing fan assembly and without raising the rotational velocity of a turbofan.
In order to achieve the above object, according to one aspect of the present invention, there is provided a blowing fan assembly for a window-type air conditioner, including a scroll case and a turbofan which is disposed in the scroll case and connected with a driving motor. The turbofan has a hub, a plurality of blades which are located at a predetermined separation from the hub and a shroud which is attached to the distal ends of the plurality of blades and positioned opposite to the hub. A depression is formed on the bottom wall of the scroll case in a manner such that the diameter of the depression is larger than the outer diameter of the turbofan, and the turbofan is positioned off-center in the scroll case in such a way as to adjoin the depression, whereby the air passage, which is defined between the shroud of the turbofan and a suction opening of the scroll case, is enlarged.
According to another aspect of the present invention, an auxiliary depression which has a wedge-shaped contour, is formed at a side of the depression on the bottom wall of the scroll case, in a manner such that the auxiliary depression is gradually reduced in a direction remote from the depression so as to allow the flow rate of air discharged out of the turbofan to be increased.
According to still another aspect of the present invention, the depression is formed in a manner such that it has a depth in the range of 10-20% of the width of the scroll case, a diameter in the range of 100-110% of the outer diameter of the turbofan, and a projecting angle of 30-45xc2x0.
According to yet another aspect of the present invention, the auxiliary depression having a wedge-shaped contour is formed in a manner such that the distance between an apex thereof and the center of the depression is in the range of 140-160% of the outer diameter of the turbofan.